1. Field of the Invention
This invention relates to a novel process for producing pyruvic acid by oxidizing hydroxyacetone with a molecular oxygen-containing gas.
2. Description of the Prior Art
Heretofore, a number of processes of producing pyruvic acid have been proposed including, for example, (1) a process in which sodium cyanide and acetyl chloride are reacted to give acetyl cyanide and the cyanide is hydrolyzed, (2) a process for dry distilling tartaric acid in the presence of potassium hydrogensulfate, (3) a process using zymotechnics in which lactic acid is used as a starting material, (4) a process for oxidizing lactic acid such as with potassium permanganate, (5) a process for oxidizing ethylene glycol, and the like processes. However, the aforementioned processes have various drawbacks. More particularly the process (1) is disadvantageous in that the starting materials are expensive and by-products are produced in large amounts, resulting in low yield and making the separation and purification of the desired product difficult; In the process (2), the starting tartaric acid is expensive and large amount of potassium hydrogensulfate used as a subsidary material is consumed; In the process (3), .alpha.-ketoglutaric acid is secondarily produced; The process (4) is coped with difficulties that the potassium permanganate is consumed in larger amount than its chemical equivalent and that the product is contaminated with a manganese compound; and the process (5) for oxidizing ethylene glycol is not suitable for selective production of pyruvic acid since by-products other than pyruvic acid are formed in large amounts.